The present invention relates generally to fluid piping systems. More particularly, this invention pertains to expansion joints for relieving heat expansion stress in a fluid piping system.
It will be appreciated by those of skill in the art that fluid piping systems designed to transport fluids in settings such as dialysis clinics, research laboratories, certain manufacturing facilities and food processing plants must be periodically disinfected.
The prior art fluid piping systems, with multiple solvent-welded joints and cavities which are relatively inaccessible for disinfection provide a suitable environment for growth of a number of pathogenic microorganisms, such as Pseudomonas species. The inventors have described, in U.S. patent application Ser. No. 09/206,904, for a "System for Fluid Delivery in a Dialysis Clinic," filed Dec. 7, 1998, the details of which are incorporated herein by reference, a novel fluid piping system which minimizes the recessed surfaces where bacteria may freely grow. However, since Pseudomonas, particularly, can grow along internal surfaces of a tube filled with sterile water, periodic disinfection of the piping system is required.
Currently, disinfection of fluid piping systems in health care clinics, particularly dialysis clinics, utilizes a combination of chemical and high temperature disinfection means. The high temperatures required for heat disinfection of conventional systems place considerable expansion stress on the piping systems. Chemical disinfectants are therefore used to allow heat disinfection temperatures to be decreased.
Chemical disinfectants, however, provide an added risk to patients in a dialysis clinic. Formaldehyde, for example, may cross dialysis membranes to enter the patient's bloodstream and stimulate antibodies to the patient's own DNA. Therefore, a more acceptable disinfection program would provide disinfection using heat alone.
What is needed, then, is a component for a fluid piping system that would facilitate heat disinfection by reducing expansion stress within a fluid piping system exposed to high temperatures for prolonged periods of time and capable of repeated cycling without compromising the integrity of the expansion compensating component.